The present invention generally relates to wheelchairs, and more particularly relates to wheelchairs that are automated and automatically controlled to shift chair position of the wheelchair in relation to the wheelchair base, in order to vary contacts, pressures, weight, and loads of the occupant against the wheelchair seat.
An occupant of the seat of a conventional wheelchair is subjected to various weight, load, and pressure contacts with the seat. These contacts can be problematic to occupants, including those occupants with certain limited capability of movement, paralysis, body aches, pains, scars or regional afflictions, and otherwise. Body contact and weight loads with respect to the seat for prolonged periods cause discomfort, and can also cause adverse medical and therapeutic problems, to the wheelchair occupant. For example, the contact pressures and weight loads can restrict blood flow, crease and press particular skin and body points, bruise the body at support contacts, cramp and consequently stiffen stationary joints, muscles and connecting tissues, and other concerns.
Such problems to the seat occupant of conventional wheelchair seats can be even more acute when the occupant is unable to easily move or shift in the seat or, at periods, forgets to periodically shift or adjust seat position. An occupant watching television, working on computer, reading or otherwise preoccupied with matters, for example, may remain stationary in the same position for prolonged times. Blood flows can be restricted for extended periods when the occupant's position does not significantly change. Contact points, weight and loads of the occupant's body against the seat and with respect to gravity, can cause injury to the occupant, including, for example, because of formations of decubitis ulcers, rash, and other skin, body tissue, and skeletal afflictions.
Decubitis ulcers (i.e., pressure sores) are a particular problem to persons who may remain stationary, or from time to time in similar position, for extended time periods in a wheelchair seat (or against other support structure, such as a bed). The occupant's body contacts and supports the occupant against the wheelchair seat (or other support). Prolonged periods of immobility in this manner can cause ulcers, rash, injury, bruising, and other medical concerns. Decubitis ulcers, in particular, can lead to open wounds and infection and are quite serious health concerns. These ulcers at times require hospitalization, surgery, and other extensive treatment, and can even be precursors to more serious ailments, infection and death. At least one study has shown that decubitis ulcers are the second most frequently occurring health problem (e.g., first is bladder infections) in persons with paralysis and immobility because of spinal injury. Richardson, R. R., Meyer Jr., P. R., “Prevalence and incidence of pressure sores in acute spinal cord injuries”, 19(4) Paraplegia 23547 (1981).
Various conventional therapies attempt to reduce medical concerns from prolonged blood flow restriction because of body contacts, weight and loading against support surfaces. A typical practice has been to manually intermittently reposition or shift a person's body, with respect to support surfaces, in order to limit periods of continuous blood restriction. For wheelchairs (and other supports), cushions containing foams, pillows, liquids, gels and air pockets have been used. These cushions are typically manually handled and repositioned at intervals, intending to spread contacts of the occupant with the seat (or other support) across the surface of the cushions. A limited number of the cushions have included mechanical or other mechanisms to somewhat firm or soften various portions of the cushion, such as by manual variation or control to vary air pressure or other supports in pockets, balloons, compartments or the like. These cushions merely affect the extent of contact and direct skin pressure at the various points. They can not significantly vary weight loading or actual position of the occupant in the seat with respect to gravitational forces. These firm/soft cushions do not provide automated or automatic adjustment features or capabilities, and manual direction and adjustment are typically required.
A person who remains in a stationary position for extended periods, such as a wheelchair or bed occupant, has not only continuous points of contact with the seat (or support), but also continuous weight loadings and pressures of the body against the seat (or support). These continuous weight loadings and bodily pressures restrict blood flows, and conventional cushions can not, themselves, significantly vary these factors. As can be understood, blood restriction concerns can be particularly acute to those with limited mobility or who do not remember to move or shift. Health concerns, including decubitis ulcers, are caused and exacerbated by this prolonged restriction of blood flow.
Certain conventional wheelchairs include manually/physically operable mechanics that can shift the wheelchair seat, for example, to recline, tilt or angle the seat. Manual/physical movement and exertion by the wheelchair occupant (and/or another person) is required to make any shift adjustment. Shifting mechanisms, in certain instances, have included powered motors and the like to aid shift adjustment. But, the wheelchair occupant (or another person), in any event, must initiate and direct the shift via manually manipulated power switch, button or similar manual interface (and also must remember to do so).
In conventional wheelchairs that have certain powered adjustment features, powered adjustment can only occur if and when the occupant (or another assisting the occupant) manually handles physical controls to do so. Hand or body manipulation through a physical interface of switches, buttons or other manually triggered devices is required to initiate and direct the adjustment. Therefore, the wheelchair occupant (or another) must remember to make adjustment and also must have sufficient manual movability, dexterity and strength to manually initiate and direct the adjustment.
U.S. Pat. No. 6,030,351 of Schmidt is an example of an attempt to provide an alarm to alert the wheelchair occupant (or assistant) to intermittently manually operate shifting mechanisms. At periodic intervals, the timer alarm intermittently sounds to alert the wheelchair occupant to manually, by hand, shift or initiate shift of the wheelchair seat. The alarm is merely a reminder alert. The occupant (or another) must then, by hand and body movement, manually initiate and direct the seat shift. Seat adjustments are not automated or automatic, and occur only when manually initially and directed.
U.S. Pat. No. 6,068,280 of the same inventor hereof describes an automatic automated seat leveler, to level the wheelchair seat with respect to the base, when the base is not level. This U.S. Pat. No. 6,068,280 provides automated, automatic leveling of the wheelchair seat, for example, as the wheelchair base passes over or sits stationary on a non-level surface. Although leveling of the seat is automated and automatic in the design, any seat shift for reasons other than leveling requires conventional manual/physical movement of hand and/or body to initiate and direct shifts.
Wheelchair occupants who may remain immobile in the wheelchair seat for extended periods (including because of paralysis, limited strength, forgetfulness, or otherwise), will not necessarily receive medical or therapeutic benefit by the prior seat adjustment features, unless the seat is manually adjusted or manually/bodily controlled (by hand or body movement to operate mechanics) for powered adjustment at intervals. In many situations, the wheelchair occupant (or assistant) can fail, forget or otherwise not take the necessary manual/body actions. Even if manual adjustment is made, the extent or effect of adjustment can be inadequate, particularly if made by those with less dexterity or other impairment. Safety concerns are raised because of potential for improper manually initiated and made adjustment. Of course, those who are physically limited in movement, dexterity or strength can have trouble manually making proper adjustment, and this may present safety issues in addition to medical/therapeutic concerns. As a result, wheelchair occupants may remain substantially stationary in the seat for extended periods, and contacts, weight loads, and pressures remain continuous and can lead to adverse medical complications as discussed.
It would, therefore, be a significant improvement in the art and technology to provide automated, automatic wheelchair seat adjustments, in order to shift a wheelchair occupant to relieve prolonged contacts, weight loads, and pressures. Such improvement can yield significant medical and therapeutic advantages and other benefits for the wheelchair occupant, as well as provide greater comfort and wider latitude in desired positioning and repositioning for the occupant.